1. Field of the Invention
The present invention is related to an ink jet recording method and a liquid dispersant.
2. Description of the Background Art
In response to demand for inexpensive recording of color images in recent years, ink jet recording methods in which ink of multiple different colors is adhered to recording media have become widely used. However, in comparison with recorded materials produced by electrophotography, the recorded material produced by such ink jet recording methods tend to have fine lines that lack sharpness or are susceptible to bleeding at the boundaries between colors. These defects stem from such characteristics as agglomeration and penetration of the ink after the ink is adhered to the recording medium, and accordingly various methods have been researched and developed in an effort to improve these characteristics.
For example, Japanese patent no. 3323565 (JP-3323565-B) describes a method of forming images by adhering a processing liquid that contains a water-soluble resin having a carboxyl group or a sulfone group to a recording medium and then adhering ink that contains an alkali-soluble resin to the processing liquid. By this method, the alkali-soluble resin contained in the ink precipitates upon contact with an acidic first liquid. As a result, the dye in the ink is fixed close to the surface of the recording medium, thereby preventing bleeding at the color boundaries to obtain quality images. However, if an acidic water-soluble resin is used for the processing liquid, modification tends to occur to the recording medium with prolonged preservation, thereby degrading the preservability of the recorded material.
Unexamined Japanese patent application publication no. 2004-130792 (JP-2004-130792-A) describes a recording method using a reaction liquid containing a polyvalent metal and a nonionic polymer and an ink that contains a coloring material, without employing an acidic water-soluble resin. According to this method, since the reaction liquid has the function of destabilizing a dissolved or dispersed state of the coloring material in the ink so that the nonionic polymer increases the adhesion property of accumulations of coloring material matters, with the result that images having excellent abrasion resistance and without color bleeding can be obtained. However, to stabilize multivalent metal ions in the reaction liquid, the reaction liquid must be acidic. In such a case, modification tends to occur to the recording medium as in JP-3323565-B described above and the preservability of the recorded material deteriorates. In addition, since the nonionic water-soluble polymer as described in JP-2004-130792-A is re-dissolved even after forming a film, water-resistant and marker-resistant properties tend to be inferior.
In recent years, a recording method using a processing liquid that contains an amphoteric ionic polymer compound and a recording liquid that contains a coloring material have been proposed, as described in JP-2004-155868-A. Amphoteric ionic polymer compounds generally have minimum viscosity at the isoelectric point (the pH at which the average charge of the entire compound after ionization is zero). Therefore, by making the difference in pH between the pH of the recording liquid and the pH at the isoelectric point of the amphoteric ionic polymer compound larger than a predetermined value, the viscosity of the mixture of the processing liquid and the recording liquid formed when mixed on the recording medium suitably increases, thereby preventing occurrence of color bleeding.
However, in the method described above, fixing of the coloring material is not considered. As a result, abrasion resistance and marker resistance are not satisfactory. That is, if a processing liquid having an amphoteric polymer is used to prevent bleeding, the obtained adhesiveness is not satisfactory.